1. Field of the Invention
The present invention relates to an electromagnetic relay, more particularly to an electromagnetic relay which is capable of facilitating an assembling process and reducing a production cost.
2. Description of the Conventional Art
As is well known in the art, an electromagnetic relay is a device to open and close a main power supply side circuit and a load side circuit.
FIG. 1 is a sectional view illustrating an electromagnetic relay in accordance with a conventional art, and FIG. 2 is an exploded view illustrating a main part of FIG. 1.
As shown in FIGS. 1 and 2, the conventional electromagnetic relay includes a contact part 10, and a driving part 30 configured to open and close the contact part 10.
The contact part 10 includes a housing 11, a fixed contact 15 fixedly disposed at the housing 11, and a movable contact 21 configured to be in contact with or separated from the fixed contact 15.
The driving part 30 includes a coil 41, a yoke 51 disposed around the coil 41 to form a magnetic path, a fixed core 61 disposed within the coil 41, a movable core 71 disposed to be close to or be separated from the fixed core 61, a shaft 81 having one end connected to the movable core 71 and another end connected to the movable contact 21, and a restoration spring 91 configured to restore the movable core 71 to an initial position.
The coil 41 includes a bobbin 45.
The fixed core 61 is inserted into the bobbin 45.
The fixed core 61 is connected to the yoke 51 to form a magnetic path.
The shaft 81 is inserted into the fixed core 61 so as to be relatively movable with respect to the fixed core 61.
The movable contact 21 is connected to one end of the shaft 81 so as to be relatively movable with respect to the shaft 81.
A compression spring 25, configured to apply pressure against the movable contact 21 to elastically contact with the fixed contact 15, is provided at an end of the shaft 81. An insertion portion 73 is provided in the movable core 71 so that an end of the shaft 81 may be inserted therein.
The shaft 81 is made of metal.
The movable core 71 and the shaft 81 are integrally coupled to each other by welding.
However, in such a conventional electromagnetic relay, when the movable core 71 and the shaft 81 are coupled to each other by welding, a lot of time and effort are required.
Further, it is difficult to identify whether the welding part has any defect or not by the naked eye, after the shaft 81 and the movable core 71 have been welded to each other.
Further, an additional device (for example, a jig for adjusting a stroke) is required to maintain a stroke between the fixed core 61 and the movable core 71 as a predetermined gap, thereby increasing a working time and requiring additional facilities.